The invention herein relates to an improved hinge system for use in prefabricated door and frame assemblies. Such assemblies conventionally comprise a door which is surrounded by and hingedly connected to a metal frame. The door, with the frame, is inserted into a doorway or door opening, as a unit. Such assemblies are commonly used in both new constructions of homes and the like buildings, as well as for replacements of existing door and door frames.
One of the problems encountered in the building construction industry is that doorways frequently are out of plumb, that is, the jambs, header and sill sections of the frame may be out of square alignment. Sometimes this comes about in a new building because of inaccurate measurements. Sometimes this takes place in an existing structure due to settling, shifting of the structure, etc.
In any event, where a complete door and frame assembly is to be inserted in a pre-existing doorway which is out of alignment, it is desirable to provide some means for aligning the door vertically, even though the door may then be slightly out of alignment with the door frame to which it is connected. That is, visually a door which is out of vertical alignment or out of plumb, is unacceptable. Vertically aligning a door is normally a very difficult, time-consuming carpentry task.
Various systems have been attempted to provide for adjustments of the door relative to the prefabricated door frame to which it is assembled. By way of example, the patent to Kempel, U.S. Pat. No. 3,690,037 issued Sept. 12, 1972 for a "Prefabricated Door and Frame Assembly" discloses, in general, the type of door and frame assembly to which the invention herein relates. The invention of this application is concerned with an improved system of adjusting one of the hinge leaves in a horizontal manner so as to preserve the vertical position of the door, relative to the frame, at all times, but meanwhile, permitting adjustment to compensate for misalignment.